This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A264279 #4 Nov 10 2015 14:51:21 %S A264279 1,10,132,4484,537057,157344756,126311779972,290106175842629, %T A264279 1813081182779342345 %N A264279 Number of (n+1)X(n+1) arrays of permutations of 0..(n+1)^2-1 with each element having directed index change 0,0 0,1 1,0 or -1,-2. %C A264279 Diagonal of A264285. %e A264279 Some solutions for n=4 %e A264279 ..0..1..9..2..3....7..0..9..2..4....7..1..9..2..4....7..0..1..2..4 %e A264279 ..5.13..6..7..4....5..1..6..3..8....0..5..6..3..8....5..6.14..3..8 %e A264279 .10.11.12..8.14...17.11.19.12.13...17.10.11.13.14...10.18.11.13..9 %e A264279 .15.23.17.18.19...10.16.24.18.14...22.15.12.18.19...15.16.12.17.19 %e A264279 .20.16.21.22.24...15.20.21.22.23...20.16.21.23.24...20.21.22.23.24 %Y A264279 Cf. A264285. %K A264279 nonn %O A264279 1,2 %A A264279 _R. H. Hardin_, Nov 10 2015